The present invention relates generally to a push button type tuner apparatus, more particularly to a push button tuner wherein a member for memorizing a preset position is positively held at the preset position without possibility of any deviation of set position, and is thus capable of carrying out preset tuning and reset tuning (re-tuning) with high accuracy.
In general, a push button type tuner apparatus is arranged so as to preset a desired station. That is, a rotatable knob is firstly turned to drive a tuning mechanism to tune the desired station, and then a push button is pressed to cause a memory plate to undergo displacement to a position in conformance with the above tuning and to clamp the memory plate thus displaced, thus memorizing the desired station. For re-tuning the preset or memorized station, the push button is pressed, which drives the tuning mechanism in accordance with the position of the memory plate which has been locked, and thus the desired station is tuned.
In push button tuners of this type known heretofore, a circular hole near one end of the memory plate is fitted on a pin of circular section, and is thus mounted pivotally on the pin. The memory plate is generally urged to move in one direction and then clamped. In this clamped state, the journal bearing part of the memory plate assumes a state wherein the inner peripheral surface of the round hole and the peripheral surface of the circular cylinder pin make contact each other at a single point, with the other parts threof being somewhat separated from each other.
Accordingly, when in the clamped state the memory plate is subject to unstable factors, and there is danger that the memory plate will be accidentally joggled or shifted at a journal-bearing part thereof when an external impact is applied thereto, thus decreasing reliability. If the memory plate is accidentally shifted, the tuning frequency to be reset through pushing operation of the push button will differ from the original preset tuning frequency, thus impairing the accuracy of the preset and reset tuning.